package com.beidasoft.web.util;

import org.apache.commons.codec.digest.DigestUtils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Created by Administrator on 2016/10/31.
 */
public class MD5 {

    public MD5() {
    }

    public String getMD5(String s) {
        char hexDigits[] = {'0', '1', '2', '3', '4',
                '5', '6', '7', '8', '9',
                'a', 'b', 'c', 'd', 'e', 'f'};
        try {
            byte[] btInput = s.getBytes();
            //获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            //使用指定的字节更新摘要
            mdInst.update(btInput);
            //获得密文
            byte[] md = mdInst.digest();
            //把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 使用MD5方法,运算传入字符串数据摘要，作为ID组成元素
     *
     * @return
     */
    public static String buildId32ByMD5(String params) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        if (null != params) {
            //加密后的字符串
            String dataDigest = DigestUtils.md5Hex(params);
            return dataDigest;
        } else {
            return "";
        }

    }
}
